Rear Brake Proportioning Valve- Butler Mod

[Freebird]

The other thing I got done today was adding the proportioning valve to my rear brakes. This is a modification that Rick Butler came up with to make the rear braking on these bikes a bit less sensitive. This is another easy modification if you get the parts from Rick as I did. I did take pictures of the installation and will try to get a tech article posted tomorrow.

 

Basically what this is though is a mini proportioning valve. You simply remove the rear brake line and screw this proportioning valve right into the rear brake master cylinder. You then install the new stainless steel line between the proportioning valve and your rear brake caliper. Bleed the brake and you are done with the install.

 

The proportioning valve is adjustable. Rick sent it calibrated the same as the one on his bike and for initial testing purposes, I left it there. These things are hand adjustable and very easy to change. The first thing I did when I got a little ways down the road was to see if I would lock up the rear brake. Yep, I still can. It took more pressure than before the modification though and that is what I was looking for. To be honest, I think it actually still locked up easier than I want it to but like I said in another post, it has rained here off and on all day so it was really not a good time to be testing it. I am pretty much convinced though that this is going to end up being one of the top modifications available for our bikes when it comes to safety.

 

Hopefully things will dry out around here a bit before the weekend is over and I can do some better testing. I may adjust it down a bit more so that it is even less sensitive yet but when I get on truly dry roads, I may find it to be fine just as it is.

[BOO]

Now this is something I might be interested in. I have been thinking about this issue for some time and have talked to several mechanics about it.

I actually was headed another direction. I wanted to link the front and the back and I think that is still possible. I seem to remember Rick doing this but having some sort of problem with it so I was just laying low to see how it turned out.

But one of the big issues with the brakes is you have way to much rear brake as you eluted to.

Keep us posted, and I looking forward to the tech write up.

Jerry

[Stoutman]

Don,

 

Thanks for the writeup. I'll be looking forward to your next update when you have some dry roads to test your brakes on. Don't put any flat spots on the new tire now.

 

I didn't see the Butler mod in the VR classifieds, but I see his writeup in the tech library has a good parts list. When this mod floats to the top of the to-do list I'll drop him a note if I need the help.

[Tartan Terror]

Is Rick selling the Mod Kit yet?

[GigaWhiskey]

Is this a Second Gen issue? I never thought any part of my brakes were sensitive. Always thought they were weak or just perfect in a corner.

[Rocket]

Is this a Second Gen issue? I never thought any part of my brakes were sensitive. Always thought they were weak or just perfect in a corner.

 

Yup, a 2nd gen thing.:bang head: Our rear & left front brakes are linked.

[Monsta]

I had made the suggestion before but I'll make it again for those who may have not heard it.

 

By adjusting the pedal DOWN you limit the ability to lock up the rear wheel. I adjusted mine down about an inch and a half (I think). I cannot lock my rear wheel unless I lift my foot completely off the floor board and stomp on it PLUS add extra force to the point where I can almost come off the seat.

 

For everyday riding and panic situations it really helps minimize lock up. Plus, it's free.

[GigaWhiskey]

Yup, a 2nd gen thing.:bang head: Our rear & left front brakes are linked.

 

I had no idea second gens were not linked, if I am reading what you said correctly.

 

If i am dropping into a sweeper or a corner a little harder than comfortable, hitting the foot brake has slouched the whole bike to where it feels safe and comfortable. Then I can goose it out of the corner.

 

If second gens are not linked, then maybe in a addition to the proportioning valve, maybe just linking them would be another solution.

 

Hmmmmm, if that is the case, first gens win again to me!

[Freebird]

Is Rick selling the Mod Kit yet?

 

Yes, I think he is. You can buy the parts and do it yourself but the valve outlet has to be re-threaded and etc. for the metric connectors and I found it more convenient to just let him do it. Made for a quick and easy installation.

[Squidley]

I'll be interested in this too as I just smoked a set of new rear pads in less than 5K and chewed the rotor up...looks like I need to send Rick a PM

[Freebird]

OK...I just did a little write-up on this and added it to the tech library. Hope it helps.

 

http://www.venturerider.org/forum/showthread.php?p=116327#post116327

[Rick Butler]

Monsta,

 

I understand completely what you are suggesting. In fact when I was doing my homework before starting on this project, I talked several riders who had previously done some racing and found it was a common practice to grind some of the pad off to provide less contact surface for the rear brake. Others old me about cutting some of the pedal off so you couldn't get your complete foot on the pedal which helped with rear lockups.

 

However in our case, we have a 4-piston caliper griping our rear rotor. This is completely TOO MUCH caliper for a rear brake,,,,,that is unless it's part of a linked or ABS braking system. In looking at other rear calipers, you mostly see small 2-piston or even 1-piston calipers. The RoadStar Warrior came with 4-piston R1 calipers and a 1-piston sliding pin caliper.

 

And even though I completely changed out the calipers on my RSV, with 4-piston calipers on the front and a 2-piston sliding pin caliper on the rear, I was still able to lock her un in a panic situation. Then I realized that the master cyclinder was designed to provide fluid flow for 4 pistons. And even though I now only have two, they were still coming out TOO quick.

 

This is when I decided to try the proportioning valve. But first I had to determine if this valve changed the pressure or the flow and tapped a gauge into the rear caliper banjo bolt. I was surprised that no matter how much the valve was adjusted closed, the pressure remained the same from what I tested without the valve. In other words, this valve just cuts down on the flow, resulting in the pistons coming out slower. This really allows you to modulate the brake pedal to suit your personal needs in stopping. If you need to stop quicker, you just press harder on the pedal. I have yet to even come close to a rear lockup with this setup. However I realize that I'm only using a 2-piston caliper, which is why I talked Don into trying it so he could provide his unbiased opinion .

 

And if you want to put stainless lines on your brakes like most of us do, this change to the rear brake is a natural. I would also reccommend EBC HH pads for the front calipers, which give you a better bite.

 

Hope helps,

 

Rick

[CrazyHorse]

When I delinked my bikes brakes I kept the proportioning valve on the rear brake works out pretty nice.

[Squeeze]

.. and tapped a gauge into the rear caliper banjo bolt. I was surprised that no matter how much the valve was adjusted closed, the pressure remained the same.....

 

Hi Rick,

 

exactly how much Pressure did you read on the Guage ???

[Rick Butler]

Well Squeeze,

 

After I saw that there was no change in the pressure with the before and after in installing the proportioning valve in-line, I went on with the project. So I really don't remember. However all is not lost, because the gauge has a movable needle that records the pressure, so I went to the garage and looked at it. It was setting at 900 psi.

 

Does this help,

 

Rick

[Spyder]

Rick,

Sorry if I missed this somewhere but how much are you selling the modified valve for?

 

Thanks,

Spyder

[Rick Butler]

Ok,

 

I hadn't really decided but here is what Don paid me just for the components, delivered to his door:

 

Proportioning Valve $ 41.45

Galfer Line & Fittings 75.00

Priority Mail Postage 6.20

 

Total: $122.65

 

It only takes me about 15 - 20 minutes to assemble everything once I get them, so it wouldn't be any more than an additional $10. However I really want to hear Don's evaluation of this product. What worked for me may not work for everyone else with all of the changes I have already made to my brake system.

 

Rick

[GigaWhiskey]

I had no idea second gens were not linked, if I am reading what you said correctly.

 

If i am dropping into a sweeper or a corner a little harder than comfortable, hitting the foot brake has slouched the whole bike to where it feels safe and comfortable. Then I can goose it out of the corner.

 

If second gens are not linked, then maybe in a addition to the proportioning valve, maybe just linking them would be another solution.

 

Hmmmmm, if that is the case, first gens win again to me!

 

I am curious, is there not a comment to this post? Rick?

[Tartan Terror]

I been thinking of doing this for a while so put me down for a kit once Don gives the writeup. If youo are assembleing all the right stuff that saves me work and Im in just give me a total number and I will paypal you.

[CrazyHorse]

I had no idea second gens were not linked, if I am reading what you said correctly.

 

If i am dropping into a sweeper or a corner a little harder than comfortable, hitting the foot brake has slouched the whole bike to where it feels safe and comfortable. Then I can goose it out of the corner.

 

If second gens are not linked, then maybe in a addition to the proportioning valve, maybe just linking them would be another solution.

 

Hmmmmm, if that is the case, first gens win again to me!

 

I would not link them you lose some of your fine control by linking. Sort of dampens your clutch, throttle, rear brake balance/relationship. I think the proportioning valve is a great idea just that little extra safety margin to prevent rear lock up.

[Squeeze]

Well Squeeze,

 

After I saw that there was no change in the pressure with the before and after in installing the proportioning valve in-line, I went on with the project. So I really don't remember. However all is not lost, because the gauge has a movable needle that records the pressure, so I went to the garage and looked at it. It was setting at 900 psi.

 

Does this help,

 

Rick

 

 

Thanks so much Rick

[Rick Butler]

Sorry Kewl,

 

When I first stated this project, I got all of the components from a 1st gen (the stock proportioning valve off the master and the metering valve for the front caliper). And with a set of custom Galfer lines, this project really took on more than I expected. First off, I had to create a billet aluminum junction to provide for one line in and two lines out (one to the proportioning valve to the rear and the other to the left front).

 

When I was talked into looking at an adjustable proportioning valve, (by my brother-in-law who was in the hydralic business) I dropped linking the brakes and concentrated on a simpler solution to the rear brake.

 

But don't get me wrong as I am BIG proponent of linked brake regardless of thier flaws for slow speed handling. And the effect of what you describe by braking going into a corner and then shooting out the other side is really created by the front brake more than the rear. The harder you press on the brake pedal, the more volume goes to the front caliper, which creates a "Trail Braking" effect. I do this by using my front brakes going into a corner, holding them a bit longer into the apex and then releasing them which shoots me out of the corner.

 

Rick

[Freebird]

Well folks, I finally got a bit of time and nice weather to do a little riding this weekend. I actually got up early this morning and took advantage of some nice cool temperatures and really enjoyed it. So, I will now give you my opinion on this brake modification. I think it is well worth the little effort and money that it requires. I had to play with the adjustment a bit. Rick is running the proportioning valve at two turns out but he has also changed his rear calipers. I have found that with the stock calipers, one turn out is a much better setting. One turn out limits the flow to the caliper more than the two turns that Rick is using.

 

I find that the brakes are now much less sensitive but still PLENTY of stopping power. Even at only one turn out, it is still possible to lock up the rear tire but nowhere near as likely as before adding the proportioning valve.

 

I have reached the conclusion that this modification is not only worth doing but from a safety standpoint, almost should be a requirement. It is possible that in a panic situation, this modification could make the difference as to whether or not you lock up and go down or come to a safe and controlled stop.

[sarges46]

I've been watching this closely as well. I have a question for Rick.....would this be adaptable for a 1100 vstar? It scares the heck outta me to watch Marilyn stop as she can and has locked the rear if stopping fast.

[Rick Butler]

Well Rick,

 

I'm not sure. In looking at the Yamaha fiche it appears like the brake line is attached via a standard banjo bolt which is a 10mm X 1.25 pitch. But I can't tell how the master cylinder is fitted to the bike and how the brake line makes it's way to the rear caliper. Saying this I see that the 1100 V-Star uses a 2 piston rear caliper which (in my opinion) is still too much rear caliper. On this bike I feel a 1 piston sliding pin caliper would suffice.

 

However if you could post some close up pictures of the V-Star master cylinder and rear brake line, I could make a more educated evaluation as to what it would take.

 

Rick